Apparatus for expanding articles



April 9 1935 s. N. JOHNSON El AL 2,937,795

APPARATUS FOR EXPANDING ARTICLES Filed Aug. 17,1955 3 Sheets-Sheet 1 96W w 98 p Q 94 7 Q a /00 I l6 H as i2 i as o k w u Q 66 74 ll I" m6 I 1I. 70 72 I ma LU we INVENTORS Sigurd AIIJo/msan Walla 0e Hall ATTORNEYApril 21, 1936. '5 N, JQHNSON ET AL 2,037,795

APPARATUS FOR EXPANDING ARTICLES Filed Aug. 17, 1953 s Sheets-Sheet 2Wallace Hall ATTORNEYA.

April 1936- s. N. JOHNSON ET AL v I APPARATUS FOR EXPANDING ARTICLESFiled Aug. 17 1955 5 Sheets-Sheet 3 2 5 4k neon Hail M ATTORNEY/ab 1VENT yard Wallace Patented Apr. 21, 1936 a r UNITED STATES PATENT OFFICEAPPARATUS FOR EXPANDING ARTICLES Sigurd N. Johnson and Wallace Hall,Anderson,

Ind., assignors, by mesne assignments, to General Motors Corporation,Detroit, Mich., a corporation of Delaware Application August 17, 1933,Serial No. 685,510

4 Claims. (01. 11344) This invention relates to an apparatus fordetoward and away from stationary die half 26 is forming tubulararticles and more particularly a companion die half 32, the surface 34of which for expanding tubes into an exponential shape. is identicalwith that of stationary die half 26.

It is an object of the present invention to pro- Die half 26 is providedwith two dowel pins 36,

5 vide an apparatus for gradually deforming proadapted to register withcorresponding holes in 5 gressive portions of a tube in one operationwithmovable die half 32, which is guided and moved out wrinkling norunduly straining the tube toward and away from die half 26 by acylinmaterial. drical bar 38, attached to die half 32 and slidableAnother object of the present invention is to longitudi a y in anOpening of a guide provide an apparatus for deforming a portion ber 42,which is attached in any suitable manner 10v of a tube into anexponential shape such that to a U-shaped bracket 44, secured to plate20 the deformed tube portion merges smoothly into by screws or in anyother suitable manner. The the tube without leaving a mark. free end ofcylindrical bar 38 is connected by These objects are accomplished byproviding togg e joints 45 and 43 190 a piston rod 50 and to diemembers, the cooperating surfaces of which a clevis 52 which is attachedto the U-shaped 5 define the desired shape of the tube, and a blockbracket 44 by a bolt 54 of said clevis and a nut 56. of elasticmaterial, such as rubber, which is placed Piston rod 50 is connec With apiston in a into a tube and then compressed in such manner Cy p V ymountedaS at 69 to a plate that the expanding portion of the blockforces 6 Wh h s Secured y Welding in y other the tube into engagementwith the die surfaces. Su ab manner to a Column mounted in y 20 Furtherobjects and advantages of the present u l manner on a Plate TWO pinvention will be apparent from the following tie-bars 66 and 68 aresecure-d by welding with description, reference being had to theaccomone end to plate 62 and with the other end to the panying drawingswherein a preferred embodi- U-shaped bracket 44, thus tying plate 62 andment of one form of the present invention is bracket 44 together.Attached in any suitable 25 clearly shown. manner to tie bar 66 is aplate 16 on which is In the drawings: mounted a valve 12. This valve isof any conig. 1 is a perspective view of a machine emventional type andis so constructed that upon bodying the present invention. shifting ofvalve lever 14 by an operator into one Fig. 2 is an enlarged fragmentaryperspective pos io One d Of Cylinder 58 s Communi- 30 view of part ofthe machine. eating with any suitable fluid pressure supply Fig. 3illustrates a conical t be t be expanded, (not shown), whereas the othercylinder side is Fig. 4 illustrates a plunger for compressing thevented. Upo Shifting of valve v 74 into the rubber block. otherposition, said one cylinder side is vented Fig. 5 illustrates the rubberblock. and said other cylinder side is communicating 35 Fig. 6 is across-section through the two shap- With t fl pressure y- COI1Sequent1y,ing dies in separated position. the shifting of valve lever 74 by anoperator re- Fig. '7 is a cross-section similar to Fig. 6, the sults inactuation of the toggle joints 46, 48, dies being shown in a position inwhich the shapeither to cause the movable die half 32 to aping of aconical tube is completed. proach the stationary die half 26 or to movethe 40 Fig. 8 is an enlarged fragmentary sectional movable die half awaytherefrom. view taken substantially on the line 8-8 of Fig. 1. Prior tothe placing by the operator of a coni- Referring to the drawings andparticularly to cal tube 16 into engagement with surface 30 of Fig. 1,the reference numeral l0 designates a die half 26, as illustrated inFig. 6, the operator machine table which supports a machine bracketfirst inserts from the wider end of said conical 45.

I2, having a bolster plate [4 and a hub l6. Setube a plunger o-r ram 18whose frustro conical cured to bolster plate 14 by screws I8'is asupportion 86 corresponds to the conical tube and porting plate 20 towhich is attached in any suitwhose lower end surface 82 is concave andbears able manner, such as by welding, a plate 22 which against theconvex end surface 84 of a frustrois also welded to two ribs 24,integral with or conical block 86 ofelastic material, such as rub- 50welded to the supporting plate 26. Attached to ber. 'This block is alsoinserted by the operator plate 22 by screws 23 is a stationary half 26of a into the conical tube prior to the placing of the die 28,'thesurface 30 of which defines the desired latter into engagement with thesurface 30 of flared or exponential shape of a conical tube, asstationary die half 26. When the conical tube I6 best shown in Figs. 6and 7 Slidable on plate 26 is properly placed into engagement with thedie 55 surface 30 of die half 26, it will be observed from Fig. 6 thatthe conical tube as well as the rubber block are resting against thesupporting plate 20 and the plunger is resting with its concave endsurface against the convex end surface of the block. Following theplacing of a conical tube into engagement with the die surface 30 ofstationary die half 28, the movable die half 32 is caused to move intocooperative engagement with stationary die half 26 by manipulation ofthe valve lever I4 by the operator.

In order to force the conical wall of tube I6 against the die surfaces30 and 34, plunger I8 is urged longitudinally in the direction of arrow81 (see Fig. 6) to compress block 88 so that the laterally expandingportion thereof forces the tube wall to be expanded into engagement withthe die surfaces 30 and 34. Plunger I8 is urged in the direction ofarrow 81 by a, head 88, longitudinally adjustably received by one end ofa cylindrical bar 90 which is guided for longitudinal movement in hub I6of bracket I2, and whose upper end is pivoted to a lever 92 which isattached by links 94 and 96 to the bracket I2. The free end of lever 92pivotally receives as at 98 a piston rod I00 of a piston (not shown)which is received by a cylinder I02, one end of which is pivotallymounted as at I04 to a lug I06 of the bracket I 2. Admission of fluidpressure to either side of cylinder I02 is controlled by a foot operatedvalve I08 which is mounted in any suitable manner to the floor plate 65.A conduit I I0 connects the valve with any suitable supply of fluidpressure (not shown), and conduits I I2 and I I4 connect the valve withthe two sides of cylinder I02. Valve I08 may be of any Well known type.In the present instance there is shown a conventional two-way valve I08actuated in a conventional manner, and since the valve does not form anypart of the present invention, no further description thereof is deemednecessary.

In order to prevent injury to the hands of the operator in case valve I2is accidentally operated so as to cause movement of the movable die halfinto engagement with the stationary die half while the operator places aconical tube between the two separated die members, the following safetyarrangement is provided. Mounted on the supporting plate 20 are spacedguide ways I20 and I22, guiding a plate I24 for movement toward and awayfrom the die members. Gib plates I26 and I28 retain plate I24 in theguideways I20 and I22, respectively. A knob I30 is attached in anysuitable manner to plate I24. Interposed between a depending lug (notshown) of the plate I24 and a bar I32 is a compression spring (notshown) which normally urges plate I24 toward the die members. When theoperator manipulates valve I2 in such manner as to cause separation ofthe die members, the plate I24 will be urged between the two die membersas soon as the latter have sufiiciently separated as illustrated in Fig.2. Therefore, if valve I2 is inadvertently manipulated as explainedabove, the die members are unable to close due to the interposition ofplate I24. At the time the operator wants to close the die members for anew operation, he first retracts plate I24 from between the die membersby means of knob I30 and holds it in retracted position until after hemanipulates valve I2 in a manner to cause the die members to move intothe position shown in Fig. 7.

Upon compression of block 86 in the manner indicated in Figs. 6 and 7,the periphery of the block at first expands uniformly and grips the Wallof the conical tube. With increasing compression of the block 88 thoseportions thereof which are closest to the plunger I8 will then at firstbe comparatively more compressed than the remainder of the block due tothe increasing frictional resistance offered by the tube wall to theblock periphery. Consequently there will first take place a deformationof that tube portion which is adjacent the top portion 86a of the block.Upon further exertion of pressure upon the block, the top portionthereof cannot expand any further due to the fact that the adjacent tubeportion is already forced into engagement with the die surfaces 30 and34; the further pressure is therefore transmitted through the compressedtop portion of the block to the next lowermost block portion whereuponanother tube portion is forced into engagement with the die surfaces.These steps repeat themselves until the entire tube portion to beexpanded is progressively forced into engagement with the die surfaces.It is therefore obvious that compression of the rubber block 86 resultsin a gradual expansion of progressive tube portions into engagement withthe die surfaces. Such gradual expansion of progressive tube portionsalso prevents the formation of wrinkles in the deformed tube wall as canbe readily understood. Experience has also taught that the transmissionof pressure from the plunger I8 to the block 86 through the concave andconvex surfaces82 and 84 respectively, thereof prevents the rubber ofblock 86 to flow between the plunger I8 and the interior wall of thetube during the compression of said rubber block and causes a mostuniform compression of consecutive layers thereof.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

What is claimed is as follows:

1. An apparatus for expanding frustro-conical hollow articlescomprising, in combination, a supporting plate; a form die adapted toreceive an article standing on the supporting plate; a tapered block ofelastic material insertable into the article and resting with its largerend surface on the supporting plate, the smaller end surface of saidblock being convex; a plunger comprising a stem of smaller diameter thanthe smallest diameter of the article and a frustro-conical portionhaving a concave end surface, said plunger being insertable into thearticle from the wider end thereof and bearing with its concave endsurface against the convex end surface of the block; and means forexerting an axial force against the stem of the plunger whereby theexpanding portions of the compressed block force the adjacent articlewall into engagement with the die surface.

2. An apparatus for expanding frustro-conical hollow articlescomprising, in combination, a forming die adapted to receive an article;a block of elastic material insertable into the article; and means forcompressing the block in the article to force the latter into engagementwith the die wall, said means including a movable ram insertable intothe article and having a concave surface engaging the blcck to transmitits compressing force to the latter.

3. An apparatus for expanding frustro-conical hollow articlescomprising, in combination, a forming die adapted to receive an article;a frustro-conical block of elastic material insertable into the articleand having a convex end; and means for compressing the block in thearticle to force the latter into engagement with the die wall, saidmeans including a movable ram. insertable into the article and having aconcave surface engaging the convex end of the block to transmit itscompressing force to the latter.

4. An apparatus for expanding frustro-conical hollow articlescomprising, in combination, a forming die adapted to receive an article;a frustro-conical block of elastic material insertable with its smallerconvex end head-on into the article from the wider end thereof; andmeans for compressing the block in the article to force the latter intoengagement with the die wall, said means including a movable raminsertable into the article from the smaller end thereof and having aconcave surface engaging the convex surface of the block to transmit itscompressing force to the latter.

SIGURD N. JOHNSON.

WALLACE HALL.

